The number of daily COVID-19 cases in India has been surging in recent weeks, and some are putting it down to a so-called double mutant COVID variant.

New case records are being set nearly daily, and the number of people dying from COVID is also growing fast.

The huge surge in cases is also being felt here, with the most recent NSW data showing people arriving from India are making up 20 percent of all cases in hotel quarantine.

So on today's Coronacast, what could be behind the surge in India?

Also on today's show:

* NZ vaccinated border worker tests positive for COVID-19

* What is the treatment for those who get the blood clots from the AstraZeneca vaccine?

* What do we know about mixing vaccines?